1. Field of the Invention
The present invention relates to an IC card and, more particularly, to an IC card having a shutter.
2. Description of the Related Art
FIG. 1 is a perspective view showing a conventional IC card 1 having a shutter 3 with the shutter 3 closed. The IC card 1 is constructed of a circuit board (see FIGS. 3 and 4) on which are mounted a plurality of electronic parts. The board is mounted in a frame 2, and panels 4 (generally metallic panels) are attached on the front and back sides of the frame 2 respectively to protect the electronic parts. The shutter 3 which is generally formed of a metallic material is slidably mounted on the front of the card to selectively open and close the IC card 1. FIG. 2 is a perspective view showing the conventional IC card, connected to an external device, having the shutter 3 with the shutter 3 opened. In this condition, a plurality of electrode terminals 6 arranged on an electrode terminal board 5 are exposed to the outside for electrical connection to an external device. The electrode terminal board 5 is mounted on the circuit board. The shutter 3 opens when the IC card 1 is inserted into the external device. The shutter 3 opens by virtue of the fact that a pin 100, disposed on a connector (not shown) of the external device, engages the shutter when the IC case 1 is inserted into the connector. The pin causes the shutter 3 to slide along shutter grooves 7 formed on the sides of the shutter 3 in a direction opposite to that of the insertion direction of the card 1. The shutter grooves 7 each include a respective opening 70 formed on a front sides of the frame 2 where the IC card 1 is inserted. The grooves 7 extend along both sides of the electrode terminal board 5 from the openings 70. Further, when the IC card 1 is pulled away from the external device, the shutter 3 closes due to the restorative tension force of springs 3a (see FIG. 5). One end of the spring 3a is mounted with screws 3b to the frame or the board, while the other end of the spring 3a is mounted on the shutter 3.
FIG. 3 is a cross-sectional view illustrating a shutter portion, taken along line III--III of FIG. 1, with the shutter 3 closed. FIG. 4 is a cross-sectional view illustrating the shutter portion, taken on line IV--IV of FIG. 2, with the shutter 3 open. As described above, the circuit board 8 is mounted to the frame 2 and the circuit board 8 includes obverse and reverse main planes on which the electronic parts 9 are respectively mounted. The electrode terminal board 5, having a plurality of electrode terminals 6 for electrically connecting the electronic parts to the external device, is arranged on one end of the obverse main plane of the circuit board 8. These electrode terminals 6 are electrically connected to the electronic parts 9.
FIG. 5 is a perspective view showing the entire conventional shutter 3 shown in FIGS. 1 to 4. FIG. 6 is a cross-sectional view showing the shutter portion perpendicular to the sliding direction of the shutter 3, taken along line VI--VI of FIG. 1. As shown in FIG. 5, the shutter 3 comprises a shutter body 3c, shutter flanges 3d which are formed by bending the right and left ends of the shutter body 3c with respect to a sliding direction of the shutter body 3c and backward extending portions 3e respectively extending backward on the right and left sides of shutter body 3c. The shutter 3 further comprises spacer portions 3f which are formed by bending parts of the extending portions 3e in the same direction as the shutter flanges 3d and spring fixing portions 3g. As shown in FIG. 6, the shutter flanges 3d are mated with the shutter grooves 7 and travel in the grooves 7. The backward extending portions 3e are provided to prevent the shutter 3 from slanting rightward and leftward during the opening and closing operations of the shutter 3. The spacer portions 3f are provided for a fixed space between the shutter body 3c and the electrode terminals 6 so that the shutter 3 and electrode terminals 6 do not contact each other. Moreover, one end of the spring 3a is mounted on the spring mounting portion 3g and the other end of the spring 3a is mounted with a screw 3b to the frame or the board. Other grooves (not shown), where the spring mounting portions 3g are fitted, may be disposed on the sides of the frame or the board. The spring mounting portions 3g may travel along the above grooves.
In such a conventional IC card having a shutter as described above, in order that the shutter be arranged to open and close over the electrode board without the shutter being lifted up, the distance denoted by character A in FIG. 3, where the panel disposed on the upper surface of the frame overlaps with the electrode terminal board, should be long. Because of the entire IC card structure, however, the distance A cannot be long. Accordingly, the shutter can be lifted up. Furthermore, if a force is added in the direction indicated by the character B in FIG. 3, the shutter may lift up, causing the shutter to be deformed.